The Hijri calendar is an Islamic lunar calendar that consists of 12 months and 354-355 days. Although the lunar months existed pre-Islamic times, the reference point for the years was introduced after the prophet Muhammad's decease. The reference year was decided in the Era of the Caliph Umar ibn Alkhattab to be the year of the migration of early Muslims from Makkah to Yathrib (known as the Hijra). Year 1 Hijri is believed to be 622AD in the Gregorian calendar.
Although the Hijra was performed in the months of Rabi Al Awwal / Safar, it was recommended by Uthman ibn Affan to continue using the established system of the Arabs to begin the year with the 1st of Muharram. This is an example of the practicality demonstrated by the early Muslims who were the most knowledgeable in terms of religion.
The Lunar Months of the Hijri Calendar are:
- Rabi' Al Awwal
- Rabi' Al Thani
- Jumada Al Oula
- Jumada Al Akhera
- Thul Qa'adah
- Thul Hijjah